Why is DNA copying an essential part of the process of reproduction?
DNA is a genetic material which carries information from the parents to their offspring by the process DNA replication in which complementary strand is made from the template strand of DNA with the help of various enzymes. If any error or mutation occurs in copying DNA, then there may be possibility of abnormality occurance in the offsprings from their parents. That’s why copying of DNA without an error is an essential process of reproduction.
Why is variation beneficial to the species but not necessarily for the individual?
Draw a labelled diagram of the longitudinal section of a flower.
What are the functions performed by the testis in human beings?
Why does menstruation occur?
How will an organism be benefited if it reproduces through spores?
Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
How does the embryo get nourishment inside the mother’s body?
What is the importance of DNA copying in reproduction?
How does reproduction help in providing stability to populations of species?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
What are plant hormones?
How is the small intestine designed to absorb digested food?
Which of the following terms does not represent electrical power in a circuit?
(a) I2R (b) IR2 (c) VI (d) V2/R
Find out about the traditional systems of water harvesting/management in your region.
Compare the power used in the 2 Ω resistor in each of the following circuits:
(i) a 6 V battery in series with 1 Ω and 2 Ω resistors, and (ii) a 4 V battery in parallel with 12 Ω and 2 Ω resistors.
How can three resistors of resistances 2 Ω, 3 Ω, and 6 Ω be connected to give a total resistance of (a) 4 Ω, (b) 1 Ω?
Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choices.
Describe double circulation of blood in human beings. Why is it necessary?
We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?
Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why?